Needle-operating mechanism for straight knitting machines



w. F. RoLs'ToN `Julyl 13 ,1926.

Dec. 21, 1925 W. F. ROLSTO'N NEEDLE OPERATING MECHANISM FOR STRAIGHT KNITTING MACHINES I 2 sheets-sheet 2 F led Dec 21 www NKWW

Parental JulyV 13, 1926.

" UNITED STATES 1,592,506 PATENT OFFICE.

HALTERl ROLSTON, 0F BOCKFQRD, ILLINOIS, ASSIGN'R OF ONE-HALF T0 WILLIAM'.

` ZIOGK, 0F ROCKFORD, ILLINOIS.

NEEDLE-OPERATING MECHANISM FOR STRAIGHT KNITTING MACHINES.

Application tiled December 21, 1923. Serial No. 681,988.

used Without stressing the yarn fibres or im.

pairing their elasticity; and consequently, to enable the knitting offiner fabrics. l have also aimed to obtain greater precision and uniformity. in the knitting,'and to produce a better quality of knitting than has heretofore been possible With such machines.

Another object isto 'mprove the construction and operation of achines of this type with the viewfto knitting easier, with Aless strain and tension on the yarn ,and less friotion on the needlesand co-operating parts. As a result, lthe needles are more accurately and positively controlled,'there is less Wear on the parts and less power required for their operation, and the life of the mechanism is increased. By relieving the strain and tension on the yarn, and for other reasons which will be apparent from the following disclosure, there' is no tendency or cause to impair,- stress or break the yarn at any time While knitting afahric, o1' after- Ward by stretching it. Furthermore, the yarn will retain its original elasticity so that, in the case of fabrics such as stockings,

theygvill retain their form and hold to the shape of the leo'.

Another object is to provide improved. mechanism whereby to permit of abrupt `changes 'intension While knitting, as for eX- ample when changing from relatively tight to loose stitchesin knitting the foot and upf lengthwiseof per portions, respectively, inv a stocking, and

' .when knitting a slack course at the top of a stocking as an identification and guide for sewing on a rib top; and it is an object to Vmake these changes inl tension without' breaking 'the yarn or impairing its strength or elasticity. t

Another object is to improve the knitting action in machines of this type especially at the critical time of` forming t'e loop.

'A further ohject is to improve the construction and koperation of the needle-rel tracting cams with the View to reducing Wear 1n the slide mountings of these cams, and consequently remedying certam maccu- -racies in-knitting and non-uniformity of Fig. 2 is an edge View of one of the needle cam slides;

Fig. 3 is a bottom View of the cam slide shown in Fig. 2, and showing a number of needle jack lugs in section;

Fig. 4 is a similar bottom view of the cam slide with the underlying parts shown `in dotted lines; and

Figs.` 5 and 6 'are detail perspective views ot one of the retracting camsr and its sectional carrier.

l'Vhile my improvements are applicable to any parallel-row straight knitting machine, IV have for purpose of illustration merely, shown them as embodied in a Burson type machine, and more particularly, .in one embodying certain other improvements forming the subject matter of my co-pending application,'Serial No. 76,142. l

In Fig; 1, I have shown in'vertical vsection the needle bed and needle-operating arts at one side of the center line indicated y the reference numeral 6, it being under-l stood that this mechanism is duplicated on the opposite side of said center line. The bed frame 7 vcarries a bed plate 8 which has upstandino portions 9 and 11 'reachin D the bed and being slotted`v crosswise thereof in comb-like fashion for the reception of sheet metal division plates designated generally by 12. These ldivision plates defined in length by inner and outer edges 13 and 14, respectively, are fur- -ther supported andheldin alignment at their rear ends by'a.`v bar 15 and Yhave lipstanding portions lconned in comb-like slots 17 in a retaining bar 18 which is held in rigid relative relation to. the said frame.

In the space between each two adjoiningJ `ferred to collectively.

"throat of the-machine and, provides an uninterrupted bearing surface on which the needie is adapted to slide back-and forth. Stationary rods 26 and 27 passing through the needle support and jack housings respectively, and also through the division plates, serve to further hold kthese parts in the desired relative relation.

The spring 24 for holding the needle down on its supporting part may be of any suitable construction, but I prefer to employ one .which is located in a stationary position and is adapted to be removed therefrom through the throat opening when removing the needle and jack as is sometimes required vfor inspection and repair of these parts. In the present instance. the spring has a shank 28 provided with a lug 29 seated in a slot in the sinker bed 31, it being manifest that by depressing the shank tlie lug 29 may be withdrawn from its retaining slot, vIurnlitting withdrawal of the spring through the throat. This spring is exceptionally light for machines of this type so as to impose less than the usual pressure onA the needle, for reasons which will be explained more fully hereinafter.

The usual sinkers 32 held in posit-ion on the sinker bed by the sinker cap 33 are adaptedt-o be advanced. and retracted by the sinker cam bar 34 in proper timed relation with the advancing and retracting of the needles asis well understood in thisiart and as will be more fully described hereinafter.

The jack housing 22 pivotally supported at its inner end. on the rod 27 is adapted to be swung on such pivot for raising and lowering the jack lug 35 into and out of operative relation to'the cams which are adapted for engaging such lug for advancing and retracting the ack and consequently its needle. The jack has a hooked inner end, the recess 36 of which receives the upturned end 37 of the needle. The jack housing or support may be raised and lowered by any suitable means, such for example as the pattern lever 23 which is pivoted on a rod 38 carried by the division plates 12. This lever has follower projections 39 and 41 which ride on theperiphery of pat-templates 42 and 43 respectively. These pattern plates, carried by the pattern cylinder, are revolved in a counter-clockwise direction viewing 1. in step-by-step movements and are so shaped as to raise and lower the jacks for bringing determined times and in timed relation with the operation of the sinkers and yarn carrier. Such` operation 'of latch needles by cams Vunder control of a pattern cylinder is well understood in this art; and it is not deemed necessary to describe in detail the complete knitting action. 'hile the construction so far described embodies certain improvements claimed in my copending apthe objects above mentioned. My improvements are therefore, primarily embodied in the construction of the needle operating cams. Such cams are carried by a cam bar slide 44 mounted in suitable bearings and adapted to be reciprocated by means of a cross head or bar (not shown) to which the sinker cam bar 34and the yarn-carrier bar (not shown) are likewise attached. The cam bal' slide carries on its under side, a pair of retracting cams also known as stitch or wing cams 45 and 46 and an advancer cam 47 also known as a center cam. Figs.

3 and 4 show these cams as Vthey appear looking at the underside of the cam bar.

spectively., The center cam having needle,

advancing faces 51, is attached to a bar 52 through means of an attaching part 53 extending through an opening 50 in the slide; and the bar 52 travels with the slide 44 and is equipped with an eccentric cam 54 adapted to be operated at predetermined times by mechanism, not shown, for raising and lowering the center or advancer cam. The ad vancer cam when lowered is in its operative position for engaging any of the jaeklugs which have been raised and advancing them and their needles; and when raised, the advancer cam passes idly over the jack lugs.

Each retracting ca m is mounted on the cam bar slide with capacity for adjustment and movement thereon in a plane parallel the 'needle-between two adjacent sinkers and extreme retracted position until positively held there. It will be here noted that the retracting face 55 of each retracting cam has an end 74 piojecting below its face 75, the purpose of which is to draw the loop down to its. greatest length and then to ielieve the loop by permitting the needles to slightly advance to the extent determined by the cam face 75. Thus when drawing a loop, new vyarn is taken from the yarn-carrier and as the loop is drawn down between the sinkers by the needle of the jack 7 6, some additional yarn is borrowed or drawn from the preceding loop (on the needle of the jack.

77), the needle of which is slightly advanced, as mentioned, to aid in giving this yarn'and t relieve its loop from stress or tension which would otherwise be imposed on this loop by the forming of the succeeding loop. It will be here noted that each filler spring 24. imposes certain friction on its needle and that in prior machines it has been necessaryto employ a comparatively heavy spring in order to lhold the needles from advancing prematurely when entering the cam way in front of the leading advancing cam face 5l, and knitting across. This heavy pressure caused excessive wear on the needles and their supports, and required greaterpower consumption. The total spring pressure on a bed is in some instances so great as to distort the bed structure, with consequent injuries. Furthermore, it is diicult in practice to obtain a satisfactory degree of uniformity of such needle pressure when comparatively heavy spring pressure is required, with the result that any relatively lighter spring will produce a tighter Wale than the adjacent wales, thereby marring'the uniformity of the knitting. According to the present invention, I employ a comparatively light filler spring .so that these objectionable features of prior -constructions iii this 'regard are obviated.

Furthermore, returning tothe point in the knitting in which the needle advances slightly after being drawn down to its extreme position, it will be observed that with a light spring pressure on the needle, the needle will be immediately advanced merely by the pull of the yarn forming the new or succeeding loop, instead of remaining'in the advanced by the follower cam 62 or until such advancing movement is transmitted to the nee'dle by such cam after aslight interval, due to wear or play in the 'connectionbetween the jack and the needle.4 In prior constructions requiring means such as a cam for positively advancing the needle after it if has been drawn down to the final point in forming the stitch, as performed'by the cam end 74 in the present case and inV which the 4heavier needle springs are required to prevent knitting across, such advancing cam,

corresponding in the present case to the cam surface engaging the jack butt 76., becomes worn and fails to return the needles to the desired position, with the result that with variations in4 pressure of these heavier springs there will be a slight variation in the length of the loops with the result that the knitting will not be uniform. According to the present invention employing a comparatively light spring pressure on the needles acertain degree of tension is relieved at the critical time of forming the loop or stitch, which makes for easier knitting and imposes less strain on the yarn, this being an important factor enabling uniform` knitting with fine yarns on this type of machine without danger of knitting across.

Another objection to prior machines is that an additional pull or tension will be imposed on each held loop, at the time the pointed end 74 of the leading retracting cam 45- (referring to Fig. 2) passesover the jack of such held loop. In said prior machines the point 74 being relatively rigid when advancing, the jack lugs are compelled to ride under said point, thereby stretching each loop. This stretching of the loop is decidedlv objectionable because it not only impairs t io strength of the yarn but sometimes .breaks the yarn. Consequently when the finished article is stretched in use, the weakened loops frequently break. Also, the stressing takes a certain amount of elasticity from the yain, so that the knitted fabric has not the desired life, and in the case of knit stockings, will not fit as well, nor have ythe life of stockings knit without this stressing. By'my invention, there is no stressing of thc yarn fibres and the yarn retains its natural elasticity. `To this end the' leading retracting cam 45'yields (as shown in Fig. 2) by reason of the pressure of the jack lug against the pointed end 74 of the cam. The pressure required for thus displacing the vcam 45 is very small and not sufficient to retract the' needles; and inasmuch as the cain passes very rapidly along the needle jacks, said cam is held in this displaced position until all of the raised jack lugs have been passed. By reason of this yielding action of the leading retracting cam or of relieving its point 74 so as not to advance the needles and stress the loops the needles are not subjected to such action askvwill cause-them to knit across as described above and as a consequence a much lighter spring pressure or tension may be imposed on each needle. As a result of this cam yielding action and the use of the comparatively lighter spring pressure on the needles I am enabled to knit with finer grades of yarn without impairing their strength or elasticity, and to produce a more uniform fabric. Another important advantage is that the knitting action is made easier and there is less wear and friction on the needles and cooperating parts. The ncam 46` functions in the same way on I kthe return stroke, that is, the camA is dis- Another advantage of the fore-going con:

- struction is that abrupt changes may be t made in the tension as when changing from knit the desired slacl n74 on lthe `thereby to the stitch-forming level of the fine or light yarns to coarse or heavier yarns,

or when changing from relatively tight to- 'loose knitting, without stressing or \breaking the loops heldl on the needles and \-without 'distorting the fabric. Thisis especially desirable for the purpose of knitting a slack course, that is, an exceptionall loose course. For example, it is sometimes esired to knit a loose course near the top of a stocking as a guide when transferring the stocking to a looper or other knitting machine for sewing on a ribbed top. In such case, when the tension is changed from the normal knitting to a comparatively loose course by means of the tension changing mechanism above described, the retracting cams will be simultaneously lowered so that a loop. of the desired length will be drawn. With prior machines of this ty it was impossible to course because the jack lugs upon encountering the projecting point leading cam would be retracted new slack course stitch to be knit with the .v .result that the held loops would be stretched and broken. With' my 40 ever, thel leading cam is displaced as above construction, howdescribed, thereby permitting the... slack course to be knit as' anyi other. One or more slack courses of this for other reasons, or for example,in Vthe knitting of any fabric as a guide for-turning a welt, or as part of a-desi And, in the" case of changin yarns an tension as when knitting a ystoc g, a change is made from a. ine or light'yarn (which 3is lmit relatively tight) toa coarse or heavier yarn knit looser),

In such case, in rior mal c` ines of this type the relatively t1 ht loops knittin heldon the needles will .be stret ed to a greater` degree stressing and possiblyl loops and distorting't e a'djacent courses ofwhereas with m J, till another advantage Ofmyimprove' ments affecting the knittmgoperation is obf ind may be desired" than usual by the leading re- Y tracting cam'"as above pointed out, 'thereby breaking such held p improvements,` y the lea ing retractin cam 1s dis laced so as tained fromthe construction and mounting of the retracting cams. Asabove described,

the carrier sections for these cams are riers in position on the underside of the caml barsllde with capacity, for ladjustment lengthwise of the ways for changing tension. As a consequence of'this construction, the continual pressure by the jack lugs against the needle retracting faces caused the bearing faces to wear unevenly and the retracting cams to be tiltedaslightly upwardly at the leading end, thereby lowering the end portion of the cam face 75 remote from its pointed end 74. This caused the lower cam face 75 to comb the held loops b reason of the de re'ssing action on the jack lugs, which was o viously undesirable. This wear developed in` such machines in spite of accuracy in the manufacture of such parts and of using case-hardened steel parts; and the cost of manufacturing suchjpa'rts was high due to distortion from hardening and to the necessary refinishing operations. According yto my invention, the cam-carrier parts and their guide plates may be made of ca'st iron,

thus materially reducing the cost of manu-` facture, and the interlocking joints aiord increased bearing surface, also the overlap- .png interlocking portions cause the lateral pressure or thrust from the cams resulting` from the needle retracting action, to be so distributed and resisted from opposed sides as to have a negligible affect on such bearing surfaces. Thus precision in operation of the retracting cams and consequently in the uniformity and quality of the resultant knitting are obtained.

It is believed a. clear understanding of the objects prefaced above. And it will be obvious to those skilled in the art that the details of structure and relative arrangement 'as herein shown might be variously modified without involv.- ing any su stantial change in the structure or its principle of operation. It should therefore, be understood that. I do not limit myself to the exact construction herein shown and described, but reserve the rig to' make' suchvariations therein as fairly I claim:

1.v In a straight'knitting machine, means whereb each retractmg cam when leadin y the held loop 'will yield .so asnot to -stress 2. In a straight knittingmachine, in comthat the foregoing conveys.

ht j al1 within the spirit and scope of the invention.`

the tension, and means whereb each retractlng cam will yield when lea ing so as not to stress the held loops.

3. In a straight knitting machine, in combination, the -needle cam slide, the stitchorming cams thereon including the retractingl cams, and means permitting each retracting cam to yield from its normal position when leading so as not to retract the needles and stress the held loops.

i 4.- In a straightknitting machine, in combination, the needles, the needle cam slide,

the retracting cams on each slide, and means 'whereby each retracting cam when leading will yield so as not to retract the needles.

5. In a straight knitting machine, in comination, the needles, the needlecam slide, the retracting cams on said slide; each retracting cam having a pointed end which retracts each needle to the maximum when forming the loop, andV means whereby each pointed end will yield so as not to retract the needles, when its cam is'leading.

6. In a straight knittingmachine, in combination, the needles, the needle cam slide, the stitch-forming cams on each slide including the retracting cams, means for changing the tensiol by adjusting both retractin'g cams to a set position in which one cam is operative durlnvr the forward stroke and the y other durin the back stroke, and means whereby eac reti-acting cam will be moved from its said set position when leading so as not to stress the held loops.

7. In a straight knitting machine, in combination, the needles, the needle cam slide,

the stitch for-ming cams on each slide including the retracting cams, means forV shifting. the retracting cams to knit a slack course, and means whereby each retracting cam when leading will yield so as not to impose additional tension on the held loops. l 8. In a stra-ightknitting machine, in combination, the' needles, the needle camslide,'

the stitch-forming cams on the slide including the retracting cams,` each retracting 'cam having a pointed end for completing' the stitch, -and means whereby saidpointed ends of the retracting cams will be rendered inoperative b yielding so as not to retract the needles w en such cams are in the leading position during any stroke.

9. In a straight knitting machine, in combination, the needles, the needle cam slide, the stitch-forming cams including the re- .tracting cams, each being movable in the lplane of its needle-retracting face for mechanism for straight knitting machines including, in`

combination, means whereby each lneedleretracting cam when leading will yield by A contact with the needle-actuating lugs so as not to stress the held loops, and liller springs imposing lcss pressure on the needles than is required in the absence of the first-mentioned means.

l2. Needleoperating mechanism" straight knitting machines including, -in combination, retracting cams, means whereby each needle-retracting cam will be moved from its normal operative lposition when leading so as not to stress the held loops, and .filler springs imposing less pressure on the needles than is required to prevent prematureadvancing of the needles in the absence of the first-mentioned means.

13. In a straight knitting machine the for combination with the needles and ai cam slide having needle-retracting cams and an' advancing cam, of light filler springs foiimposing such lightpressure on the needles as to /pernut each needle to be advanced under the yarn pull or tension immediately on each retracting cam allowing each needle to be so advanced, and means whereby each -retracting cam will yield when leading so as-not to stress the held loops and whereby such retracting cam will not act on the needles so as to cause premature advancement thereof.

14. Needle-operating mechanism for stra-ight knitting machines, including needle-ret-racting cams and an advancing cam, means whereby each retracting cam will be displaced from its normal operative position when'leading so as not to affect the normal position of the needles, and means for imposing comparativelylight pressure on the needles permitting each needle to be advanced under the yarn pull immediately after its loop is drawn to the fullest extent by the retracting cam, the displacing of said leading retracting cam eliminating any such action on theneedles as to cause premature advancement thereof especially with lighter needle pressure.

15. Needle-operating mechanism for straight knitting machines including needleretracting cams, and means-whereby each retracting cam when leading will be dis- `ing cam from its normal operative position.

16. ln a st-raight knitting machine, in combination, a cam slide, a cam, and a mountin for the cam on the slide comprising a re ated and tongued bearing joint.

17. In a straight knitting machine, in combination, a cam slide, a cam, and a mounting for the cam on the slide comprising larebated and tongued bearing joint having end bearing faces andan intermediate bearing face in parallel planes transverse to the pressure strains on the cam.

18. In a StraightV knitting machine, in combination, the-needle cam slide, the needle retracting cams, a sectional carrier for each cam, tension-changing meansattached to. one of theV carrier sections for each cam, anda spring for holding the carrier sections for each together and permitting relative movemcntbet'iveen said sections.

19. In a straight knittingv machine, in'

anda spring yieldingly holding the l'carrierv sections togetherand .permitting relative* movement therebetween. v

20. Needle-operating mechanism v for straight knitting machines including, in combination, a cam slide, needle-retracting cams, a sectional carrier for each retracting cam, one section of eachjcarrierbeing slid-- able on the cam slide in a piane parallel with the needle retracting face 'of its retracting cam, means connected with both slidable 'carrier sections for adjusting them t vary the tension, each retracting cam being fixed to the other carrier section which latter is'movable in said plane toward and from its first-mentioned carrier section, and a spring acting against each retracting cam to hold it in its normal operative position and permit it to yield therefrom when leading so as notto stress the held loops.

21. Needle-operating mechanism for straight knitting machinesl comprisino in combination with the needles, of a cam glide,

vneedle-retracting cams and an4 advancing cam, each retracting cam having a pointed end adapted for drawing the needles down to the final position when forming the loop toallow the needles to advance slightly to va determined position after drawing the loop, and means for causing each retracting cani when leading to be displaced from its normal position so as to not stress the held loops, said displacing movement taking place .independently of movement of the other retracting cam and While it is in its normal operative position for retracting the needles. i

22. Needle-operating mechanism n for straight knitting machines comprising, a cani slide, needle-retracting cams and an advancing cam on said slide, a sectional carrier for each reti-acting cam, the retracting cam being fixed to one of the carrier sections, the other carrier section having means exiendingthrough the calnslide and adapted to be adjusted for varying the tension,

means mounting both carrier sections on the .cam slide so that they are movable in a plane parallel withthe. needle-retracting face of' the retracting cam, means connected with e the carrier adjusting means for each retracting cam for simultaneously moving fsaid f cams to increase or decrease the tension, and

means4 whereby each retraeting cani when leading will be displaced so as not to-impose additional tension on the held loo s.

WALTER F. ROL TON. 

